<template>
	<div>
		<router-link 
			tag="div" 
			to="/" 
			class="header-abs"
			v-show="showAbs"
		>
			<div class="iconfont header-abs-back">&#xe624;</div>
		</router-link>
		<div class="header-fixed" v-show="!showAbs" :style="opacityStyle">
			景点详情
			<router-link to='/'>
	        	<div class="iconfont header-fixed-back">&#xe624;</div>
			</router-link>
		</div>
	</div>
</template>

<script>

export default {
 	name: 'DetailHeader',
 	data (){
 		return {
 			showAbs: true,
 			opacityStyle: {
 				opacity: 0
 			}
 		}
 	},
 	methods: {
 		handleScroll (){
 			const top = document.documentElement.scrollTop
 			if( top > 60 ){
 				let opacity = top / 140
 				opacity =  opacity > 1 ? 1 : opacity
 				this.opacityStyle = { opacity }
 				this.showAbs = false
 			}else{
 				this.showAbs = true
 			}
 		}
 	},
 	activated () {
 		window.addEventListener("scroll", this.handleScroll)
 	},
 	deactivated () {
 		window.removeEventListener("scroll", this.handleScroll)
 	}
}
</script>

<style lang='stylus' scoped>
	@import '~styles/varilbes.styl'
	.header-abs
		position absolute
		left .2rem
		top .2rem
		width .8rem
		height .8rem
		line-height .8rem
		border-radius 100%
		background-color rgba(0,0,0,.8)
		text-align center
		.header-abs-back
			color #fff
			font-size .4rem
	.header-fixed
		position fixed
		top 0
		left 0
		right 0
		height  .86rem
		line-height .86rem
		background-color $bgColor
		color #fff
		font-size .32rem
		text-align center
		z-index 2
		.header-fixed-back
			position absolute
			left 0
			top 0
			width .64rem
			color #fff
			font-size .4rem
			text-align center
</style>			
				
